Looking for an AC Adapter for MZ-1

[PaoloB 0]

I just made a quick and dirty check by bridging the fuse and... it just works! Any suggestion on where to source an exact spare or equivalent? Even though some web links are suggesting that Sony 1-533-282-21 is a 2A/72V, the unit is reading a “50” on the small case, suggesting - maybe - 5A (which seems a tad overrated)...

Thanks!

[NGY 28]

I am glad to see that early unit coming back to life.

2 hours ago, PaoloB said:

some web links are suggesting that Sony 1-533-282-21 is a 2A/72V, the unit is reading a “50” on the small case, suggesting - maybe - 5A

Yes, this P/N is a 2A fuse. Rated 2A, while the "50" stands for the 5A fusing current. See the extract from the datasheet:

With that, you can just buy any microfuse that is rated similarly, and has the same form factor (i.e., 3.2×2.5mm footprint).

 

EDIT: be careful when soldering the new fuse. You need to use an old style solder (before RoHS) with lower melting point (around somewhere 220...240 °C), and do not heat the fuse for more than a few seconds, keeping a short break (say a minute) between soldering the two contacts.

[PaoloB 0]

Just swapped the fuse with a good one taken from a donor board (damaged unit). Must say I missed the caveat about the solder temperature and used 260 deg C. Luckily, it seems as though I did not damage the fuse, so the unit is alive again. As for the power brick, I will in any case replace the capacitor with a new one: I’m sure the old one is OK (can’t measure it, though), but you never know.

I attach a picture of the fuse for future reference.

Thanks again for your support, I’m really grateful I could learn something new.

Paolo

[PaoloB 0]

Hi All, 
Update on the power brick. Today I replaced the big capacitor (in case, be careful, always discharge it before touching its pins) with a “new, bigger, better” one (of course: same capacitance).
No surprise, though. Output voltage is still around 18 V with 220 V nominal input (in fact, the original capacitor looks just fine, no bulging, no leaking whatsoever).
MZ-1 units work.
However, what indeed puzzles me is that under load the output voltage drops just slightly, down to some 16 V. Way much above the indicated, and - I’d assume - expected 10.5 V, plus minus.
If plugged into a 120 V outlet, you get in between 8 and 9 volts. Sufficient to power up the minidisc unit, but not to operate it (e.g. eject would not work).
So, it’s not even a “universal” power brick of some kind just differently labeled depending on the plug and final market of destination. Would be interesting to know the actual range of voltages the unit can handle...